Field of the Invention
The invention relates to a unidirectional centrifugal mechanism, and particularly, to a unidirectional centrifugal mechanism of a door operator for a fireproof rolling door, making the rolling door having the functions of fireproof, smoke prevention, and escape.
Description of the Related Art
For a general fireproof and smoke prevention rolling door driven vertically or horizontally, a door curtain of slats slides down to close a door with its own weight, so as to effectively block smoke or flame generated during a fire accident. It can be understood that the weight of a rolling door curtain, especially, a large-sized rolling door curtain, is quite heavy, and hence in case it loses control in speed, its dropping due to acceleration of gravity, must cause a destructive power.
As such, an industry manufacturer is always demanded of a strict design for safety, to guarantee that, no matter the door curtain rises or falls, any dangers caused by human factors or machine factors should not happen. Accordingly, a door operator for a general fireproof rolling door is basically provided with a “centrifugal brake mechanism”. Thus, when a fire accident occurs and the door curtain slides down automatically to close the door by its own weight, the falling speed of the rolling door for fireproof and smoke prevention is controlled within a predetermined safety range.
For an emergency exit rolling door and an escape rolling door, they are exactly opposite to each other in structure according to their different functions and purposes. However, In case of a fire accident, they must be kept unblocked and easily opened. Therefore, for a manufacturer, many different controlling types of door operators must be developed in order to response to the requirements for different installation sites, functions and purposes. Accordingly, not only development time is long and cost for the development is high, but also the number of parts is large, which renders production complicated, and inventory cost relatively increased.
It is known that many documents are related to door operators for fireproof rolling doors. For example, U.S. Pat. No. 5,203,392 and U.S. Pat. No. 5,386,891 are proposed. For the disclosure of the above-mentioned patent publications, in the case of no braking during a power outage, the door curtain of slats slides down to close up door by its own weight so as to effectively block smoke or flame generated by a fire accident. On the other hand, if the door curtain of slats must be opened in an emergency for an escape during a fire accident, although the door curtain of slats can be driven to move up by a manual pull-chain mechanism, it takes a lot of time and consumes much more physical strength, and causing a late escape.
Although the manual pull-chain mechanism is used to open the door curtain of slats, a person having ordinary skills in the art is ready to understand that the centrifugal brake mechanism of a traditional door curtain of slats can not only be used to retard the falling speed of the fireproof rolling door or the smoke prevention rolling door, but also can retard the rolling door opening, which resulting in a late door opening.
The inventor thinks that if a centrifugal brake mechanism of door operator retards the falling speed of the door curtain of slats only in one directions but doesn't effect normal opening thereof in the other direction in spite of the case of emergency, then the door operator can be used for the purposes of fireproof, smoke prevention, and escape all together, that is to say, the structure of the door operator and its production are simplified to relatively reduce development and inventory costs thereof.